Introduction:

When we use the EM Spectrum for communication, we set up transmitters and receivers. In this activity, we will use Infrared Remotes as transmitters, and the Macbook camera as a receiver.

Activity:

• Open Photobooth, choose the Effect called Thermal Camera, and switch to Record Movie (command-T).
• Aim the remote control at the Macbook camera and press-and-hold a variety of keys (you will need two distinct patterns to study).
• Drag the video clip to your desktop and double click it. (The video should open in QuickTime Player.)
• Study the patterns in the Infrared beam and see if you can detect a pattern in the signal that would transmit a different code for different keys.

Conclusion:

Infrared signals are part of the EM spectrum that are not visible with the naked eye. However, special receivers can detect the code and display the transmitted signal in a way that we can see.

Practice:

The Infrared part of the spectrum is a lower frequency than the light that is visible to our eyes. You can practice your understanding of the range of EM radiation with the following Quia quiz.

E3 EM Spectrum

Enrichment: